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Growing Wetlands to Protect Rivers – and the Future of Agriculture

In Illinois, Tony Bonucci turns to a ‘constructed wetland’ to reduce nutrient loss from his farm

Sometimes individual actions can be the catalyst for bigger change.

That’s what Tony Bonucci believes is needed to protect his land – and the future of agriculture and the environment in the Midwest.

In August 2016, the north-central Illinois farmer converted a five-acre piece of land into a small wetland area to naturally filter nitrogen from tile water draining from his corn and soybean fields. Drain tiles are pipes that are buried in fields to quickly remove excess moisture.

The decision was prompted by Tony’s concern about the amount of nutrients being lost from his land and being washed downstream into the Mississippi River.

“By turning this piece of the field into a wetland, it should be possible to remove lots of nutrients from the water before they get in our rivers, our streams, and ultimately into the Mississippi River basin,” says Tony, who farms 4,400 acres with his brothers near Princeton, Illinois. “It's one tool to address a much bigger water quality problem.”

The Mississippi River and its tributaries have been plagued by nutrient runoff, specifically excess nitrogen and phosphorus, for decades. These nutrients, in the form of fertilizer, are essential to growing soybeans and corn in the Midwest but are often unintentionally lost to rivers and streams.

About 40% of streams in the Mississippi watershed are impaired by nutrients which ultimately end up in the Gulf of Mexico. They have triggered rapid overgrowth of algae and created an 8,700 square mile hypoxic ‘dead zone’ of depleted oxygen in the Gulf.Not only do lost nutrients become a pollutant, but they cost farmers’ money.

“Economically you don’t want to be putting on more fertilizer than necessary. If you are losing 25% of it, it’s some serious money that you are just really throwing away,” Tony says.

Tony worked with the Wetlands Initiative, an Illinois-based conservation nonprofit, to build the 'constructed wetland' along lower-lying edge of a field that feeds into a creek. The area often collected standing water from drainage tiles in the field.

The new wetland, which is designed to hold up to 12 inches of water, captures and removes nitrogen, turning it into a harmless gas.

It is surrounded by another four acres of pollinator buffer, native grasses and plants that prevent surface runoff to the wetland area. As a secondary benefit, these native plants can provide habitat for the monarch butterfly and other declining pollinators.

“It's only a small piece, a little under five acres, but it's a nice little area to have a little biodiversity, a place for wildlife,” Tony says.

Jill Kostel, senior environmental engineer with the Wetlands Initiative, says constructed wetlands make sense on tile-drained farmland and are most effective in marginal land areas on the field’s edge. They are highly effective and require little maintenance once built.

“Drainage tiles allow farming to be very productive, but the problem is when the water leaves the field, it is carrying everything that can possibly be dissolved in the water,” says Jill. “It’s a leaky system.”

The constructed wetland is “just a little interception point” for tile water coming off a field, she adds.

These wetlands typically do not have a lot of open water and are chock full of vegetation that provides a carbon source for bacteria that denitrifies the water. Unique to this site design on Tony's land are small pumps that deliver the tile water directly to the wetland.

The Wetlands Initiative staff works with farmers to decide how and where to build the wetland, targeting marginal or unproductive land.

“Our goal is not to take the world’s best farmland out of production. We want to take the worst ground out of production and give farmers a solution to the problem of nutrient runoff,” says Jill.

In partnership with the University of Illinois at Chicago, the Wetlands Initiative has installed equipment to measure nutrient levels in water coming into – and leaving – Tony’s field.

“We get a clear unbiased picture of nutrient loss,” Tony says. “We think we are doing a good job holding our nutrients, but unless you measure it you don’t really know.”

The Walton Family Foundation supports the Wetlands Initiative’s work with farmers in Illinois on implementing constructed wetlands. These wetlands offer one way to carry out the state’s Nutrient Loss Reduction Strategy, which promotes a suite of practices to reduce water pollution caused by agricultural runoff.

“It’s a big issue from a conservation standpoint. You want to leave the soil in better shape than when you got it,” says Tony. He and his brothers are also planning to start planting cover crops as an additional way to improve soil health and water quality.

“If farmers don’t take care of these things on their own, someone is going to end up mandating it down the road. These problems aren’t going to go away on their own.”

Sheldon is a communications officer at the Walton Family Foundation, focused on editorial and digital content creation.

Roots of Conservation is a series of stories about the people working to address threats to water quality and soil health in the Mississippi River Basin and find conservation solutions that make economic sense for people and communities.